Spindle motor having blind hole configuration detail and hard disk drive device having the same

Abstract

A spindle motor includes a base being a cast product as a part of a housing of a hard disk drive device. The base has a hole portion configured to accommodate a fastening member configured to fasten a member to be attached to the base. The hole portion is a blind hole extending in a depth direction from a surface of the base and having a tip surface formed flat.

The invention claimed is: 
     
         1 . A spindle motor for use in a hard disk drive device, comprising
 a base being a cast product as a part of a housing of the hard disk drive device, wherein   the base includes a hole portion configured to accommodate a fastening member configured to fasten a member to be attached to the base, and   the hole portion is a blind hole extending in a depth direction from a surface of the base and having a tip surface formed flat, and has a pilot hole depth which is obtained by adding an effective screw length, an incomplete screw length, and a margin length in the depth direction from the surface of the base, and   the margin length is corresponding to less than 0.5 pitches of the effective screw length.   
     
     
         2 . The spindle motor according to  claim 1 , wherein
 a shortest distance between the tip surface and a bottom lower surface of the base facing the tip surface is from 0.5 mm to 2.0 mm.   
     
     
         3 . The spindle motor according to  claim 1 , wherein
 the hole portion includes an inner wall surface extending in the depth direction between the surface of the base and the tip surface, the inner wall surface being formed with a female screw to be screwed with a male screw as the fastening member.   
     
     
         4 . A hard disk drive device comprising:
 the spindle motor according to  claim 1 , the spindle motor being accommodated in the housing and including a rotating portion configured to rotate with respect to the base;   a recording disk accommodated in the housing and supported by the rotating portion;   a magnetic head accommodated in the housing and configured to perform recording of data on the recording disk and reading of data recorded on the recording disk; and   a cover forming the housing, as the member to be attached.   
     
     
         5 . The hard disk drive device according to  claim 4 , wherein
 the housing contains a gas having a density lower than a density of air.   
     
     
         6 . The hard disk drive device according to  claim 4 , comprising a plurality of recording disks accommodated in the housing and supported by the rotating portion, wherein
 at least seven of the plurality of recording disks are provided with a predetermined gap.